PROJECT SUMMARY/ABSTRACT This application is a request for continuation of support for a pre-doctoral Training Program in Virology at Yale University. The goal is to provide multidisciplinary research training to predoctoral students in the molecular biology of viruses, virus-host interactions, and pathogenesis in human viral diseases. This is expected to provide the intellectual and research foundations necessary for productive careers in virology-related disciplines in academia, industry, and government. The program offers training in virtually all aspects of modern virology including viral genetics, the molecular, cellular and structural biology of viruses, adaptive and innate immune response to viruses, virus-host interactions at the cellular and organismal levels as well as translational research towards the treatment of viral diseases. The program is co-directed by Drs. Priti Kumar and Walther Mothes, and a 5 member Advisory Committee. The program has been strengthened by the addition of new Faculty trainers and courses to cover emerging critical areas of virology. As a group, the 22 trainers have an outstanding record of research accomplishment and training and many are national or international leaders in their fields. These trainers have primary appointments in 14 different Yale departments and currently have 51 predoctoral virology trainees working in their labs. Students enter the program through the Combined Program in Biological and Biomedical Sciences (BBS). The BBS unites nearly 375 faculty in basic biological and biomedical sciences at the Yale Medical School, Science Hill on the main University Campus, and the newly developed West Campus. Admission is granted to students with outstanding academic record with particular attention to research experience. The Faculty makes extensive efforts to attract and retain trainees from diverse backgrounds, particularly under- represented minority groups. The program is supported by strong institutional commitment to graduate training. Predoctoral training leading to the Ph.D. degree involves formal course work and laboratory rotations in the first year. This provides a solid and broad conceptual foundation and experimental training in microbiology, immunology, cell biology, genetics, as well as other areas of biology. Students select a research advisor at the end of the first year and defend a research proposal in a qualifying exam at the beginning of the second year. A Thesis Committee monitors student progress throughout the thesis research process. Intensive training in the methods, logic, and responsible conduct of research are supplemented with a wide array of opportunities for teaching and scientific interactions. The median time to obtain the Ph.D. degree is 5.4 years. This application requests funding to continue support for four predoctoral trainees in each year, with each trainees supported by this grant for a maximum of two years.